Determination of inorganic antimony species in seawater by differential pulse anodic stripping voltammetry:stability of the trivalent state

摘要

A simple method is described for the rapid and reliable deermiantion of ultratrace concentrations of Sb(III0 and Sb(V) in seawater by differential pulse anodic stripping voltammetry.It is based on the well-known dependence of Sb(III)/Sb(V) in seawater by differential pulse anodic stripping voltammetry.it is based on the well-known dependence of Sb(III) /Sb(V) voltammetric response on acidity conditions.Under our optimised conditions (0.5 mol l~9-1) HCl for Sb(III) and 5 mol l~(-1) HCl for total Sb,respectively):(i) a detection limit of 11 ng l~(-1) is obtained for a 10 min deposition time;(ii) no prior elimiantion of organic matter is needed;and (iii) antiomony can be determined in thepresence of natural copper levels.particular care has been takeninorder ot understand the chemical processes taking place in all the solutions and reactionsinovlved in the sampling and measureing procedures.Our results revealed the need to consider (i) the efect of photooxydatio of synthetic and seawater samples on Sb speciation;and (ii) thestability of Sb(III) both in seawater samples and in the analytical solutions.